Branched-chain hydrocarbon elastomers

ABSTRACT

THE INCORPORATION OF A C5 TO C110 POLYOLEFIN HAVING TWO POLYMERIZABLE DOUBLE BONDS ADDED IN AN AMOUNTS OF FROM 0.01 TO 0.5 GRAM-MOLES/KG. IN EPDM ELASTOMER PRODUCES CHAIN BRANCHING WITH A CONSEQUENT IMPROVEMENT IN PROPERTIES SUCH AS COLD-FLOW OF THE UNCURED STOCK, AND IMPROVED OZONE RESISTANCE OF NATURAL RUBBER BLENDS.

United States Patent O Int. Cl. C08d 3/02, 3/04, 9/02 US. Cl. 26080.7838 Claims ABSTRACT OF THE DISCLOSURE The incorporation of a C to Cpolyolefin having two polymerizable double bonds added in amounts offrom 0.01 to 0.5 gram-moles/kg. in EPDM elastomer produces chainbranching, with a consequent improvement in properties such as cold-flowof the uncured stock, and improved ozone resistance of natural rubberblends.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is acontinuation of application Ser. No. 38,862, filed May 19, 1970, nowabandoned which, in turn, is a continuation-in-part of application Ser.No. 625,598, filed Mar. 24, 1967, now abandoned.

BACKGROUND OF THE INVENTION This invention relates tosulfur-vulcanizable, chainsaturated elastomeric, a-olefin copolymershaving improved coldflow. More particularly this invention relates toimproving the ozone resistance of blends of chainunsaturated dienepolymers with sulfur vulcanizable, chain-saturated, elastomeric a-olefincopolymers by the introduction of a controlled amount of chain branchinginto the a-olefin copolymer.

Among the polymers of the aliphatic olefins that are made by use ofcoordination complex compounds of the transition metals aspolymerization initiators, the amorphous copolymers of ethylene withhigher alpha-monoolefins constitute an important class because of theirdesirable elastomeric character and their generally excellent resistanceto ozone and other chemicals. The chemical inertness of these polymersis attributed to the fact that the linear chain or backbone is acompletely saturated structure without the reactive double bonds of thecommon elastomeric materials such as natural rubber or the syntheticelastomers made from conjugated diolefins. This chemical inertness madethe early polyolefin elastomers, namely amorphous ethylene-propylenecopolymers, impossible to vulcanize with the sulfur systems preferred inthe rubber industry. This problem was solved by incorporating as thirdmonomers, non-conjugated diolefins containing both a readilypolymerizable and a relatively nonpolymerizable double bond, thusforming an elastomeric polymer consisting of a linear saturated backbonehaving pendant unsaturated hydrocarbon groups capable of participatingin crosslinking reactions with sulfur curing systems. The use ofnon-conjugated aliphatic diolefins such as 1,4-hexadiene and6-methyl-1,5-heptadiene as the third monomer in hydrocarbon elastomersof this sort is taught, for instance, in US. Pat. 2,933,480, and the useof bridged ring diolefins having double bonds of unequal reactivity issimilarly taught in US. Pat. 3,211,709.

It is the nature of coordination complex polymerization of olefinhydrocarbons to form practically linear, unbranched polymer chains.While a strictly linear polymer structure is advantageous in the stiff,crystalline poly- 3,819,591 Patented June 25, 1974 olefins used asthermoplastic molding materials, such as polyethylene and polypropylene,it is not necessarily so in amorphous polyolefins that are used aselastomers. As a matter of fact, it has been found that strictly linearpolyolefin elastomers show relatively undesirable coldfiow propertiesunless the polymer has an especially broad distribution of molecularweights. For example, the undesirable cold-fiow properties cause theelastomer to rupture bags in which they are packaged during storage.However, such a distribution of molecular weights causes undesirablyhigh viscosity of dilute solutions of the polymer in the solventsemployed in their manufacture and use.

DESCRIPTION OF THE INVENTION The present invention provides sulfurcurable chainsaturated branched elastomeric amorphous copolymersconsisting essentially of (a) from 25 to by weight of ethylene units,

(b) units derived from a C to C polyolefin containing two polymerizabledouble bonds, said polyolefin units being present in an amount resultingfrom the addition to the reaction mixture from which said copolymer isformed of about from 0.10 to 0.5 gram mole per kilogram of copolymerformed of said C -C polyolefin the amount of the polyolefin not toexceed 15% by weight of the copolymer, and

(c) sufiicient units of a nonconjugated diolefin containing only onepolymerizable double bond to provide 0.1 to 4.0 gram mole/kilogram ofpolymer of carbon-carbon double bonds derived from the diolefincontaining one readily polymerizable double bond; and

(d) the remainder of said copolymer being propylene units,

said polymers being prepared by an organo-soluble coordination catalyst.

The present invention also provides a sulfur curable ozone resistantcomposition consisting essentially of about 10 to 30 parts by weight ofthe copolymer of this invention and about to 70 parts by weight of apolyunsaturated elastomer.

As used herein, the term consisting essentially of has its generallyaccepted meaning as requiring that specified components be presents, butnot excluding unspecified components which do not materially detractfrom the basic and novel characteristics of the composition asdisclosed.

Methods for carrying out the polymerization of olefin hydrocarbons withcoordination complex catalysts are well known in the art. See, forinstance, Linear and Stereo-Regular Addition Polymers, by Gaylord andMark, Interscience Publishers, New York, 1959. Among the most usefulcatalyst systems for making elastomeric copolyolefins are those based onsoluble compounds of vanadium such as vanadium oxytrichloride, vanadiumtetrachloride, vanadium tris-(acetylacetonate), etc., used inconjunction with organoaluminum compounds such as aluminum alkyls (e.g.,triisobutyl aluminum), and alkyl aluminum halides (e.g., diisobutylaluminum chloride), and so on. It is preferable that a halogen bepresent on at least one of the catalyst components. Many variations andrefinements of these catalyst systems are now well known in the art. Theparticular organo-soluble catalyst system used is not critical to thepractice of this invention as long as it is capable of formingpractically amorphous copolymers of olefin hydrocarbons.

A variety of solvents can be employed with the catalyst. Among the mostuseful are tetrachloroethylene, and aliphatic hydrocarbons such ashexane. Other solvents wil be apparent to those skilled in the art.

Methods for copolymerizing ethylene and propylene to form amorphouspolymers that have the basic characteristics of a synthetic rubber arewell known in the art. The principle of making such polymersvulcanizable with sulfur curing systems by introducing a thirdpolymerizable monomer a multiolefin having only one polymerizable doublebond is also known. Polymerizable double bonds in coordinationpolymerization systems are generally found to be unhindered terminaldouble bonds in aliphatic olefins, or double bonds in strained ringcycloaliphatic compounds, such as cycloaliphatic compounds having oneortwo-carbon bridged ring structures. Double bonds that are found not tobe readily polymerizable are generally the internal, i.e., non-terminaldouble bonds of aliphatic olefins, sterically hindered double bonds ofaliphatic olefins such as those carrying a methyl group or othersubstituent on one of the doubly bonded carbon atoms, and double bondsin relatively unstrained cycloaliphatic rings. Typical non-conjugateddiolefins containing only one polymerizable double bond that aresuitable in copolymers of this invention are 1,4-hexadiene,2-methyl-l,5-hexadiene, 1,9 octadecadiene, 6 methyl 1,5 heptadiene,7-methyl 1,6 octadiene, 11-ethyl-1,1l-tridecadiene, and the like.Typical cycloaliphatic compounds that can serve the same purpose includedicyclopentadiene, tricyclopentadiene, S-ethylidene-Z-norbornene,-methylene-2- norbornene, alkenyl substituted norbornenes having aninternal double bond in the alkenyl group (e.g., 5-(2'-butenyl)-2-norbornene), unsaturated derivatives ofbicyclo(2,2,2)-octane, and so on. The use of such compounds to providependant sulfur-reactive unsaturated structures on an amorphouspolyolefin is well known in the art.

Amorphous copolyolefins including ethylene, propylene, and one or moreof the above-mentioned diolefins made by the prior art methods aremainly straight-chain polymers and have the disadvantages alreadymentioned.

A desirable ramification, i.e. chain branching, can be introduced intopolymers of the general class by including a carefully selectedproportion of a fourth monomer that has two polymerizable double bonds.As used herein, the

term polymerizable double bon is meant terminal, unhindered double bondsin the main chain structure of the monomer, and the double bonds instrained ring cycloaliphatic structures. Suitable monomers may containtwo terminal double bonds, two strained ring double bonds, or one ofeach.

The monomers generally suitable for incorporation as the fourth monomerare C to C polyolefins. The amount of the polyolefin is not to exceed15% by weight of the copolymer. Incorporation of larger amounts ofpolyolefin produces a copolymer which yields an impractical curingformulation. For example, whereas 2 to 4 parts of sulfur are generallyrequired to cure an EPDM elastomer, 8 to 10 parts of sulfur may berequired when the polyolefin in the copolymer of this invention exceedsweight percent.

Typical monomers suitable for this purpose are 1,4- pentadiene,1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, 1,20-heneicosadiene,'5-(5-hexenyl)-2-norbornene, 5-(2- propenyl)-2-norbornene, and the like.A particularly suitable diolefin having two strained ring double bondsis the reaction product of norbornadiene-2,5 and cyclopentadienehavingthe following structure For simplicity, this compound will becalled norborneo norbornene, although its systematic name is l,4,4a,5,8,1' 1 bridged ring units by further condensation with cyclopentadiene canalso be used, such as etc.

2,5-norbornadiene can be used, and the dimer thereof, which can berepresented by the formula is especially useful.

Other monomers suitable for incorporation as the fourth component arealiphatic and aromatic compounds having two terminal allyl groups. Theallylic radical is represented by the formula CH CHCH with each radicalfurnishing one polymerizable double bond when terminally located.Particularly suitable are compounds of the following formula:

where R is (CH with x=0-29, or phenylene, alkyl substituted phenylenes,naphthalene, polybutadiene, polyisoprene, polystyrene,poly-a-methylstyrene, butadiene-styrene copolymer, butadiene-isoprenecopolymer, isoprenestyrene copolymer, or polyvinylnaphthalenes.

When esters, ethers, or any monomer containing a hetero-atom, such asoxygen, sulfur or nitrogen, are present during polymerization, it ispreferable to complex the hetero atom to facilitate polymerization. Thisis conveniently accomplished by using an excess amount of organoaluminumcompound in the coordination catalyst system as will be apparent tothose skilled in the art.

Analysis of the amount of monomer having two polymerizable double bondsincorporated in the polymer has in some cases provide difficult. Theproportions described herein and in the following examples are theproportions employed in the synthesis. During the synthesis, it ispreferred that the conversion of the diolefin containing only onepolymerizable double bond be at least 20 percent. Also, it is preferredthat the conversion of the polyolefin containing two polymerizabledouble bonds be at least 20 percent; as conversion is increased, asmaller amount of the polyolefin is required to obtain the desiredbranching.

In the case of linear diolefins containing two terminal allyl groups theefficiency of the diterminal olefin as a modifying agent appears toincrease with chain length to about 8 carbon atoms. Diterminal olefinshaving 8 or more carbon atoms are most efiicient. It is accordinglypreferred to employ a-w-diolefins containing from 8 to 35 carbon atomsas the modifying agent.

The branched copolymers of the present invention consist essentially ofa linear chain or backbones with branching along the chains. Thesebranched copolymers differ from previously known EPDM copolymers havinga practically linear structure. Chain branching is demonstrated by thefact that the copolymers of this invention have physical propertiessubstantially different than those of practically linear copolymers,such as known EPDM copolymers. The properties of the copolymer used todetect branching are the solution (inherent) viscosity and bulkviscosity as indicated by the Wallace plasticity. For example, theinherent viscosity and Wallace plasticity of a practically linearcopolymer and a branched copolymer are measured as described in thefollowing examples. The results are compared, and the branchedcopolymers shows a greater rate of change in Wallace plasticity than therate of change in inherent viscosity. Thus, for a given inherentviscosity, the Wallace plasticity is greater for the branched than forthe unbranched copolymer.

Mooney viscosity is measured at 121 C. in accordance with ASTM MethodD1646-67 using the large rotor. After the sample has been warmed in themachine for one minute, the shearing disc viscometer motor is started tobegin the test. Fourminutes later the reported viscosity reading istaken.

Wallace plasticity is a measure of the amount of flow or deformation ofunvulcanized elastomeric materials under load. The sample to be testedis sheeted and cut into pellets having a thickness in the range3.18-6.35 mm. (0125-0300 inch). The test is preformed with a Wallaceplastimeter manufactured by H. W. Wallace and Co., Ltd., London. Duringa IO-second period the pellet is simultaneously compressed to exactly1.0 mm. in thickness and heated to 100 C. The resulting test piece isthen subjected to a kg. load'for exactly seconds at 100 C. The finalthickness of the test piece, expressed in units of 0.01 mm., is theplasticity value reported. The standard 1-cm.diameter platen is suitablefor pellets of average hardness. Proper platen temperature regulation ismost important because elastomer plasticity is usually temperaturedependent. Plasticity readings should normally fall between and 90 onthe scale for most reliable readings.

The elastomeric products of the present invention can be processed withconventional rubber processing equipment in the same way as other sulfurcurable a-olefin based elastomers, particularly those elastomers havinga broad molecular weight distribution.

Conventional compounding ingredients such as carbon black, mineralfillers, coloring agents, extending oils and the like are generallyincorporated into the polymers. Various curing systems can be employed,as will be apparent to those skilled in the art. The most important ofthese curing systems is the sulfur curing system which is applicable toall of the polymers within the scope of this invention. Other curingsystems include quinoid curing systems, phenolic curing systems andperoxide curing systerns.

The polymers of the present invention have improved cold flow resistancewhen isolated, compared with elastomers having the same proportions ofingredients and made with the same catalyst but omitting the modifyingamount of diolefin containing two polymerizable double bonds. The aboveimprovement is indicated by the increased Wallace Plasticity. As shownin the examples, the Wallace Plasticity of the products can besubstantially increased without any substantial increase in solutionviscosit This invention is further illustrated by the following specificexamples. All parts, proportions, and percentages are by weight unlessotherwise indicated.

EXAMPLE 1 Production of Ethylene/Propylene/1,4-Hexadiene/ 1,7-OctadieneCopolymer The following general procedure is used. A one-liter ml. of1,4-hexadiene. The rapidly stirred solvent is then presaturated withethylene and propylene at flow rates of 1 and 2 liters/min,respectively, the feed stream being introduced below the surface .of thesolvent. The flow of gases to the resin flask is then left unchangedthroughout the subsequent polymerization. The ethylene and propylene aremetered through separate rotameters at aback pressure of 3 psi. andcombined at a three-way joint before being introduced into the resinflask. The ethylene and propylene are dried individually by passagethrough a two-foot high column of Molecular Sieve, Type 5A. After thesolvent has been presaturated, polymerization is initi ated byintroducing 5 ml. of a 1.0 Molar solution of diisobutylaluminum chloridein tetrachloroethylene and 5 ml. of a 0.1 Molar solution of vanadiumtrisacetylacetonate in benzene by means of hypodermic syringes. Theflask contents are kept at 25 C. by external cooling with a DryIce-acetone bath for a period of thirty minutes, after which time 10 ml.of a 1% solution of 4,4'-thio bis(6-tbutyl-m-cresol) in isopropylalcohol is added to stop the polymerization.

1,7-octadiene, a diolefin having two readily polymerizable double bonds,is added at a constant rate throughout the thirty-minute reactionperiod. The octadiene is conveniently handled in the following way: Asmall quantity of 1,7-octadiene, shown to be 97% pure by vapor phasechromatography, is passed through a short column of alumina, theeflluent collected under nitrogen and the desired amount is accuratelyweighed into a volumetric flask where it is diluted with 200 ml. heptaneand stored under nitrogen. A control is prepared with no 1,7-octadiene.

After the reaction has stopped, the feed streams are shut off, and thepolymer solution is washed with 200 ml. of 5% hydrochloric acid untilthe organic phase is colorless. The organic layer is separated andwashed twice more with 2.00 ml. proportions of water. The solvent isallowed to evaporate from the polymer solution in a porcelain pan. Thecopolymer produced is obtained as a thin film which is dried at C./ 105mm. for 24-36 hrs. The reaction is repeated three more times withvarying quantities of 1,7-octadiene. The resuts are described in Table1.

Propylene content is determined from the infrared absorption spectrum,and 1,4-hexadiene content is determined from the infrared absorptionspectrum or by bromine absorption. Inherent viscosity is determined on a0.1% solution of the polymer in tetrachloroethylene at 30 C. The amountof insoluble polymer found is determined by heating one gram of sampleone day at C. in ml. of 'tetrachloroethylene with no agitation. Theresulting solution is filtered through a tared 200 mesh screen. Thescreen is dried and weighed. The substantial increase in bulk viscosityof the polymer that is achieved by incorporating 1,7-octadiene, withonly minor change in solution (inherent) viscosity, is shown by theWallace Plasticity values for the resulting polymers.

TABLE I E/P/1,4 HD/1,7-octadiene copolymers Wt. percent 1,7- octa-Wallace diene, Percent Yield, Pro- 1,4-hexplasmoles/kg. insolgramspylene adiene ticity mun polymer ubles Exmilple 1: 19 49 2. s 42 2.14.067 0. s 19 49 4. 3 22 1. 81 034 0. 5 20. 7 51 2. 7 19 1. 79 016 0. 419 49 3. 2 19 1. 79 0 0. 2

Control.

EXAMPLES 2-5 resin flask is equipped with a stirrer, thermometer, a gasinlet tube, a rubber (serum) cap and gas outlet tube. The resin flask,stirrer, gas inlet tube and gas outlet tube are dried in anoven at 65 C.and mm. pressure for at least thirty minutes before use. One-half literof heptane which has been dried over silica gel and sparged withProduction of Ethylene/Propylene/Hexadiene Copolymer With Various DienesHaving Two Readily Polymerizable Double Bonds Incorporated Therein -In areactor as in Example 1 is placed 500 ml. of tetrachloroethylene whichhas been dried over silica gel and nitrogen is introduced into the resinflask along with 3.4 75 sparged with nitrogen, and 3.8 ml. of1,4-hexadieue. A

combined stream of nitrogen, ethylene, and propylene is introduced atflow rates of 0.5, 1,-and 2 liters/minute, respectively.Reactiontemperature is C. Diene with two readily polymerizable doublebonds is then added as indicated in Table II, and polymerization isinitiated with ml. of a 1.0 Molar solution of diisobutylaluminumchloride and 5 ml. of 0.1 Molar vanadium compound as shown in Table II.The reaction is allowed to proceed for -20 minutes, and the polymer isisolated'as in Example 1.

Table II shows the desirable effects on plasticity and cold flowproperties of severaldienes having two readily polymerizable doublebonds. 1,4-pentadiene and 1,7-octadiene are readily available diolefinsof this class. 1,20- heneicosadiene is prepared fromheneicosa-1,20-diene-l1- 8 to the solvent before the catalyst andco-catalyst are added. The diisobutylaluminum chloride and vanadiumtrisacetylacetonatesolutions are injected, and the .polymerization isallowed to proceed for fifteen minutes during which time 18 ml. of themethylenenorbornene solution is added dropwise at a constant rate. Thetemperature is kept at C. throughout the polymerization. Thereaction isstopped and the copolymer is isolated as' in Examples 1-4. This productis the control of. Table III.

The reaction is repeated except thatjust beforethe catalyst andco-catalyst are injected intothe resin flask, an 0.052 Molar1,7-octadiene solution in tetrachloroethylene is added. Fiveml'. of thesolution is used in Example 6A, and 10 ml. inaExample 6B. The resultsare summarized in Table III. i

*Gram-moles of H C=CH- per kilogram of polymer.

one by Wolf-Kishner reduction, the 'ketone having been made fromll-undecenoyl chloride by the method of Sauer, J. Am. Chem. Soc., 69,2444 (1947). The 5-(5- hexenyl) norbornene is prepared by the method ofUS. Pat. 3,144,491, Vanadium components of the catalysts are vanadiumtrisacetylacetonate, V(AA) and vanadium oxytrichloride, COCl The greatlyincreased bulk viscosity of the polymers with increasing incorporationof dienes with two readily polymerizable bonds, even though solutionviscosity is little affected, is shown both by the Wallace Plasticitydata and by the Cold Flow data.

Cold flow is measured at 100-102" C. in the following manner. A deviceis assembled such that weighed brass cylinders (124-125 g., 19.5 mm. indiameter) freely sliding through holes in a one-inch iron plate willexert a pressure of 0.6 p.s.i. on a molded cylindrical pellet of thepolymer resting on another iron plate. The height of the pellet ismeasured before and after a period of heating in an oven and the resultsreported as percent compression set, i.e. (change in height/originalheight) 100. The pellets are in. in diameter and /2 in. in height, ascalled for by ASTM D945-59.

EXAMPLES 7-9 Production of Ethylene/Propylene/1,4-Hexadiene/Norborneo-Norbornene Copolymer Polymer samples are preparedaccording tothe method described in Examples-Z-S. Norborneo-norbornene is preparedaccording to the method of J. Stille, J Am. Chem. Soc., 81, 4273 (1959).The norborneon orr hormone is passed through a short column of neutralgrade Woelm alumina and diluted with perchloroethylene to prepare asolution approximately .025 Molar in diene. The desired quantity ofdiene solution is'then 'f added to the reaction flask at the timedescribed in Ija'ble IV by means of a hypodermic syringe.. g I 1 It canbe seen from the results in Table IV'that only a very small quantity ofnorborneo no'rbo'rnene isnecessary to profoundly alter the bulkviscosity characteristics of the sulfurvulcanizable terpolymer. 7 I

TABLE II Wt. percent Reaction 1,4 Moles/ Wallace time, Yleld,Propylhexakg. 4th plastio- Cold Vanadium Example min. grams ene diene4th monomer monomer ity mun, flow catalyst 2,Cor1trol 20 20.5 49 3.6 "030 2.17- 1 s7 0.13 as 2. 26 4e voila 22g g 0. 29 39 2. 33 18 37 2.17 5715 16.0 51 3.7 lilizo'henelmsadlene 0. 03 as 2. 20 37 i? g g 0. 07 51 2.2G 2 0 3O 2. 67 55 15 11.5 49 as Pfl-" 0. 09 as 2.22 s

. 2. 12 71 V AA 15 14.5 50 4.2 Fdihexenybmrmmene 0. 017 35 1. 99 14vEAAi: 15 16. 5 {)3 3. 7 0. 031 2. 68 2 EXAMPLE 6 65 Production ofEthylene/Propylene/S-Methylenenorbornene/1,7-Octadiene Copolymer In areactor as in the previous Examples, using the procedure described inExamples 2-5, except at a reaction temperature of 25 C., an ethylene,propylene, 5- methylene-norbornene terpolymer is prepared. The 5-methylene-norbornene is added in the following way: Two ml. of asolution consisting of 5.0 gm. of S-methylene- 2-norbornene in 110 ml.of tetrachloroethylene is added An E/P/norborneo-norbornene terpolymeris prepared by the method of Examples 2-9 except that no 1,4-hexadieneis used and the polymerization is conducted at 25 C. The product isdesignated Control Y. The-reaction is repeated but with nonorborneo-norbo r'nene'being added to the reaction fiask in order topreparean'ethylene-propylene copolymer, designated Cont'rolZlfTheresults are ShQWIl in Table v.

(NBNB) COPOLYMER TABLE rv.-PuoDuo'rroN OFETHYLENEIPROPYLENE/1,4HEXADIENE/NORBORNEO-NORBORNENE l Quantity ReactionNBNB Wt. I added, Wallace Percent percent Time, 7 Temp. Method ofmoles/kg. Cold plas- Yield, propyl- 1,4-hexa- Example min. v C. NBN Baddition polymer flow ticity Tlinh, grams ene diene 7, Control i 10 0 e32. 7 2. as 10 44 3.6 10 V, 0 .029 2 70 2.63 8.5 44 4.1 10 '-'0' 0 32.22.07 11.0 50 3. 2 10 0 All after 026 55 2.18 9. 5 43 3. 9 0 0 19.5 1.6816 52 3.6 15' 0 .029 25 1.70 17 53 3. 7 15 0 d 059 34 1. 86 17 51 3. 915 0 --d0 0- 10 39. 5 l. 86 15 48 3. 6

TABLE V The results are reported in Table VII. Control polymerscontaining no diolefin having only one readily polymerizable double bond15 TABLE VII Moles/kg. 4th Wallace Percent Moles/kg. Yield, propyl-Bromine norborneomonomer plastmty Control g. flinh. ene equiv. norbomene18 1 61 z 1s 1. 64 7o o. 04 o 51 Y 2o 1. 74 68 o. 04 0. 037 20 78 53Norm-Neither C ontrol Y nor Z is curable by sulfur curing ingredients.

EXAMPLE 12 EXAMPLE 10 Production of E/P/l,4-Hexadiene/Bicyclo(2.2.1)-Hepta- 2,5-Diene (2,5-Nonbornadiene)Copolymer Ethylene/propylene/1,4-hexadiene polymers were preparedaccording to the method described in Examples 2'5 except that 7 ml. of lMolar diisobutylaluminum chloride was used as cocatalyst. Thebicycloheptadiene was distilled and passed through a short column ofalumina before use and used as 0.052 Molar solution intetrachloroethylene. The amount designated in Table VI was added justbefore the catalyst and cocatalyst.

TABLE VI Moles bicycloheptadiene/ Wallace Yield kg. polymer plasticityflinh. (5-) It can be seen that with increasing bicycloheptadienecontent that the bulk viscosity went up rapidly whereas there was only aminimal increase in inherent viscosity.

EXAMPLE 11 Production of E/P/1,4-Hexadiene/Dimers of Bicyclo-HeptadieneCopolymers Polymer samples were prepared as in Example No. 10. Thebicyclo(2.2.l)-hepta-2,5-diene dimers were prepared by heatingbicycloheptadiene with a bis(triphenyl phosphite) nickel dicarbonylcatalyst for 36 hrs. in toluene. The isomeric dimers so prepared havethe structure designated thus:

Preparation of High Diene Content E/P/HD/OD Tetrapolymer To a 2-literresin kettle equipped with a mechanical stirrer, thermometer, additionfunnel and syringe inlet, and dried thoroughly with a heat gun under anitrogen atmosphere, is added 884 ml. of anhydrous hexane, 116 ml. of1,4-hexadiene and 1.0 ml. of 1,7-octadiene. The stirred mixture iscooled to 17- -3 C. while being saturated with ethylene fed at a rate ofthree gram moles per hour and propylene fed at a rate of 0.1 gram moleper hour. A 2.33 ml. portion of pure diisobutylaluminum chloride isadded followed by a dropwise addition of 20 ml. of a 0.1 M solution ofVCl in perchloroethylene over a period of 21 minutes. The temperature ismaintained at -17- *-3 C. for 30 minutes after the addition of VCl isbegun. The polymerization is stopped with the addition of a hexanesolution containing about 3.0 ml. of isopropanol and 0.5 grams of4,4'-thio-bis(6-tert-butylmeta-cresol). The isolated polymer contains8.4% of propylene by weight and 2.61 moles/kg. of ethylenicunsaturation.

EXAMPLE 13 A. Preparation of a,w-Diallylpolybutadiene A 2-liter flaskwas fitted with a magnetic stirrer, a thermometer, a condenser and twoaddition funnels (one of which had cold fingers suitable for coolingwith crushed solid carbon dioxide). After the entire assembly had beendried with heat under a nitrogen atmosphere, one liter of anhydrous,reagent grade tetrahydrofuran, fifty grams of reagent grade naphthalene,and 2.1 grams of clean lithium ribbon were added in turn to the flask.The temperature was held at 25-30 C. until the lithium was completelydissolved (2.6 hours). Then the solution was cooled to -45 C. Butadiene(92 ml.), which had been dried by passage through a molecular sievetower, was collected in the cold addition funnel and added to the flaskduring a 15-minute period. The resulting solution was allowed to warm to--10 C. in thirty minutes and held at 10- -5 C. for one hour to preparea,w-dilithio polybutadiene. Then a total of thiryt-nine milliliters ofanhydrous allyl chloride was added dropwise while the temperature waskept at 0:5 C. The deep red color disappeared when twenty-threemilliliters of allyl chloride had been added. Finally, a solution of0.139 g. of 4,4'-dithiobis(3-methyl- 6-tert-butylphen0l) 'in a mixtureof isopropanol/hexane (1:8 by volume) was introduced. After the solventshad been evaporated at reduced pressure, the resulting residue was steamdistilled until all the naphthalene was removed. The viscous residue wasseparated from the water phase and finally dried at reduced pressure atC. The u,wdiallylpolybutadiene obtained thereby weighed 74.5

grams and had a number-average molecular weight of 480 (by vapor phaseosmometry).

The polymerization was carried out continuously by using a liquid-full,1.2-liter, stainless steel reactor maintained at a pressure of 100p.s.i.g. The following feed rates were established:

Ethylene, 2.365 gram-moles per hour; propylene 4.55 gram-moles per hour;1,4-hexadiene, 0.207 gram-moles per hour; a,w-diallylpolybutadiene, 2.56grams per hour; VOCl .076 millimole per hour; triethylaluminum, 1.39millimoles per hour; diethylaluminum chloride, 0.793 millimoles perhour; benzotrichloride, 1.95 millimoles per hour; hydrogen, 2.25millimoles per hour; and hexane, 1.903 liters per hour.

The average residence time was thirty minutes. The reactor temperaturewas maintained at 35 C. by external cooling. Polymer was produced at anaverage rate of 100.6 grams per hour. The reactor efiiuent wasdischarged into a flasher where unreacted ethylene and propylene wereallowed to evaporate at atmospheric pressure. The residual polymersolution was then mixed with a solution of 4,4-thio-bis(3-methyl-6-tert-butyl phenol) in an isopropanolhexane mixture(1:8 by volume) before catalyst residues were removed with dilute aceticacid and water washes. Hexane was removed by evaporation on a drumdrier. The isolated tetrapolymer had the following monomer unitcomposition: 2.5% a,w-diallylpolybutadiene, 38.8% propylene, 3.1%1,4-hexadiene, and 55.6% ethylene (by weight). The inherent viscosity ofthe polymer was 1.86 (measured at 30 C. on a solution of 0.1 gram oftetrapolymer in 100 ml. of tetrachloroethylene); the Mooney viscosity(ML-1 +4 at 121 C.) was 38.

The branched-chain elastomeric copolymers of this invention have beenfound to be especially useful in blends with polyunsaturated elastomerssuch as natural rubber and the synthetic diene elastomers. It is knownin the art that the EPM and EPDM elastomers confer a measure of ozoneresistance on such blends, but it has surprisingly been found that thebranched-chain tetrapolymers of this invention are much more elfectivethan the prior art terpolymers, as illustrated by the followingExperiments.

EXAMPLE A The following compositions are prepared by standard laboratoryrubber milling procedure and vulcanized in test slabs for minutes at 163C.

Specimens of the vulcanizates are tested for ozone resistance by ASTMmethod D 1149, at 50 and 300 parts ozone per 100 million (p.p.h.m.). Asshown by the data of the Table VIII, the octadiene-modified tetrapolymergives a blend with natural rubber having substantially better ozoneresistance than the prior art EPDM terpolymer.

' "'1; -B .I. CR /f Ozone resistance 0180:20 natural rubberlcopolyrnerblends Rating i Blend B 50 p.p.h.m. ozone: Dynamic:

25 hr 300 p.p.h.m. ozone: Dyria c:

hr 10% elongation:

1 0w 5 hi. a. 2 '10 b 1=no efiect; 8=notlceabl visual racking heaectacki'n 0 rea Y in.

natural rubber, 30gramsof-neoprenmtypeiw, ,.5 gram s of zinc oxide, 25grams of FEF carbon black, and 3.0 grams of Circosol Light -0i1;* -'Thenthe following curing ingredients consisting of. 0.5 gram of (2,2i-dithibisbenzg thiozole, 0.35 gram of'l p e v stearic acid and 1.3 igra'mofulfur'wei'e' a ded'at about 50 C. on a 4 x.8".,rubb ei:.-milllabs,,.made-fro resulting stock, werecured to 1,5. I L3 tween Mylarpolyestersheetst Dumbe lls er cu wi th a die and clamped in theflilgynarnat attachment"in,;.a chamber at 40 C. er maintained at 0.5p.p.m n

a period of up to 24 hours. I p y pfz-Eztamp e. resistance to theblends, whereas a co stituting a tripolymer of ethylene, propylene and1,4-hexadiene (made by a-smiliar'process-)-*for'the-tetrapolymerdisplayed poor ozone resistance- The branched-chain elastomeric copo yvention have been retina. to "be espe au pser gm blends withpolyunsaturated elastomers, suchasna a1 rubber, and the synthetic dieneellastomersgParticularl styrene/butadiene elastomers (e.g.- SBRcOntaamng23.5% styrene by weight),polybutadienefand 'butadiene/acryloi i -g-NBRh4 I1g 29fl5%;=? Y QB I rubber, styrene/b i ferred. I

addition to. the. reacti .nnxture'i w h 'sa polymer is formed of aboutfrom 0.01 to... 5 mole per kilogram of copolymer' formed of Cpolyolefin, the amount iof the polyolefin not to exceed 15% by i'ivveiglht'ofi elcopolymer,

(c) sufiicient unitsgof a nonconjpgated diolefin containing only onepolymerizable donble bond selected from the group consisting of (1) analiphatic diolefin, and (2) a cycloaliphatic compound having a oneortwo-carbon bridged ring structure to provide 0.1-4.0 gram moles perkilogram of carbon-carbon double bonds derived from the diolefin, and

(d) the remainder of said copolymer being propylene units.

2. A composition of claim 1 wherein diolefin (c) is dicyclopentadiene.

3. Composition of claim 1 wherein polyolefin (b) is 1,7-octadiene.

4. Composition of claim 1 wherein polyolefin (b) is norbornadiene.

5. Composition of claim 1 wherein polyolefin (b) is norborneonorbornene.

6. Composition of claim 1 wherein diolefin (c) is 1,4- hexadiene.

7. Composition of claim 3 wherein diolefin (c) is 1,4- hexadiene.

8. Composition of claim 4 wherein diolefin (c) is 1,4- hexadiene.

9. Composition of claim 5 wherein diolefin (c) is 1,4- hexadiene.

10. Composition of claim 1 wherein diolefin (c) is 5-ethylidene-Z-norbornene.

11. Composition of claim 4 wherein diolefin (c) is 5-ethylidene-Z-norbornene.

12. A composition of claim 1 wherein polyolefin (b) has two double bondsin a strained ring cycloaliphatic structure.

13. A composition of claim 1 wherein polyolefin (b) has two unhinderedterminal double bonds.

14. A composition of claim 1 wherein polyolefin (b) has one double bondin a strained ring cycloaliphatic structure and one unhindered terminaldouble bond.

15. A composition of claim 12 wherein diolefin (c) is an aliphaticolefin.

16. A composition of claim 12 wherein diolefin (c) is a cycloaliphaticolefin having a oneor two-carbon bridged ring structure.

17. A process for preparing branched elastomeric copolymers havingimproved properties which consists essentially of copolymerizing in thepresence of a coordination complex catalyst, a mixture of:

(a) ethylene in an amount sufiicient to provide from 25% to 75% byweight ethylene units in the copolymer,

(b) propylene,

(c) nonconjugated diolefin containing only one polymerizable double bondselected from the group consisting of (1) an aliphatic diolefin, and (2)a cycloaliphatic compound having a oneor two-carbon bridged ringstructure added in an amount sufficient to provide 0.1 to 4.0 gram molesper kilogram of carbon-carbon double bonds in the resulting copolymer,and

(d) C -C polyolefin added in an amount of about from 0.01 to 0.5 grammole per kilogram of resulting copolymer, said polyolefin containing twopolymerizable double bonds and added in an amount such that the unitsderived from said C -C polyolefin do not exceed 15% by weight of theresulting copolymer.

18. A process of claim 17 wherein the coordination catalyst containshalogen.

19. A process of claim 18 wherein the coordination catalyst containssoluble compound of vanadium.

20. A process of claim 19 wherein the coordination catalyst containsorganoaluminum compound.

21. A process of claim 20 wherein the polyolefin has two unhinderedterminal double bonds.

22. A process of claim 20 wherein the polyolefin has one double bond ina strained ring cycloaliphatic structure and one unhindered terminaldouble bond.

23. A process of claim 20 wherein the polyolefin has two double bonds ina strained ring cycloaliphatic structure.

24. A process of claim 20 wherein the polyolefin is norbornadiene.

25. A process of claim 20 wherein the conversion of the polyolefincontaining two polymerizable double bonds is at least 20%.

26. A process of claim 20 wherein the polyolefin is norborneonorbornene.

27. A process of claim 20 wherein the nonconjugated diolefin is analiphatic olefin.

28. A process of claim 24 wherein the aliphatic olefin is 1,4-hexadiene.

29. A process of claim 23 wherein the nonconjugated diolefin is acycloaliphatic olefin having a one or twocarbon bridged ring structure.

30. A process of claim 29 wherein the cycloaliphatic olefin is alkenylsubstituted norbornene having an internal double bond in the alkenylgroup.

31. A process of claim 29 wherein the cycloaliphatic olefin isS-ethylidene-Z-norbornene.

32. A process of claim 31 wherein the polyolefin is norbornadiene.

33. Composition of claim 1 wherein said polyolefin units are present inan amount resulting from the addition to the reaction mixture from whichsaid copolymer is formed of about from 0.0l50.29 gram mole per kilogramof copolymer formed of said C -C polyolefin.

34. Composition of claim 4 wherein norbornadiene units are present in anamount resulting from the addition to the reaction mixture from whichsaid copolymer is formed of about from 0.0180.14 gram mole ofnorbornadiene per kilogram of copolymer.

35. A process of claim 17 wherein said polyolefin is added in an amountof about from 0.015-0.29 gram mole per kilogram of copolymer.

36. A process of claim 24 wherein norbornadiene is added in an amount ofabout from 0.018-0.14 gram mole per kilogram of copolymer.

37. A composition of claim 1 wherein diolefin (c) is an alkenylsubstituted norbornene.

38. A composition of claim 4 wherein diolefin (c) is dicyclopentadiene.

References Cited UNITED STATES PATENTS 3,554,988 1/ 1971 Emde et a1.26080.78 3,444,146 5/ 1969 Valvassori et al. 26080.78 3,651,009 3/ 1972Cameli et al 26080.78 3,652,729 3/1972 Brodoway 26080.78

JOHN C. BLEUTGE, Primary Examiner US. Cl. X.R.

mg UNITED STATES PATENT OFFICE V I CERTIFEQATE @F (IQRRECTION Pat No.3,519,591 Dated w 25. m

Mentor) g m and Eabert Dean'ihu m I it is certified that error appearsin the above-identified*patent and that said Letters Patent are herebycerrected as shown below:

31%. 6, insert w 9 m E. '3. flu Font da Honour! and;

' g 1,1,, #3 aargamfiim: of Delawm w man; 6 1 u,

15m 32 the am fihwld read V0613 if, the swims mated unfiar "V diumcatflylt f9 "iji'jr, anfi a 5 lPP as "5" I V001 raapectively. 1

main 2! ulwuld read A proceam a? alum 23 n.

Signed and sealed this 22nd day of October 1974.

(SEAL) Attest: MQQOY gzzssow JR. c. MARSHALL DANN Attestimg @fficerCommissioner of Patents h after fim mm @mfimm @2 5 ms 1mm, column 1,31

